Methods for measuring the vertical axis of super high-rise buildings

Abstract

This invention discloses a method for measuring the vertical axis of a super high-rise building. For the bottom floors, a total station is used with an external control method for vertical transfer. For the remaining floors, a reference floor and several floors above it are selected as transition layers for setting up the axis control network. Calculations are performed to ensure that the theoretical projection accuracy of each transition layer is within the allowable range. Then, a laser plumb line is used with an internal control method to vertically transfer the axis control network upwards segment by segment. After each re-laying of the axis control network at the transition layer, a GNSS measuring instrument is used to check and correct the axis control network, correcting the accumulated error of the previous stage of vertical projection to zero and ensuring that the actual accuracy of the baseline edge and network shape is within the allowable range before upward transfer. This invention improves the effectiveness and reliability of vertical measurement of high-rise buildings and greatly shortens the measurement time.

Description

Technical Field

[0001] This invention belongs to the field of engineering surveying, and specifically relates to a method for measuring the vertical axis of a super high-rise building. Technical Background

[0002] Due to their towering structures, the lateral deflection, torsion, and sway caused by diurnal and seasonal temperature differences, sunlight, and wind loads in super high-rise buildings cannot be ignored. Furthermore, the limited site space for super high-rise buildings, coupled with natural and construction conditions, increases the difficulty of measurement, rendering ordinary measuring tools and methods unsuitable for construction surveying of super high-rise buildings. Summary of the Invention

[0003] The purpose of this invention is to provide a method for measuring the vertical axis of super high-rise buildings, which improves the effectiveness and reliability of vertical measurement of high-rise buildings and greatly shortens the measurement time.

[0004] The technical solution adopted in this invention is:

[0005] A method for measuring the vertical axis of a super high-rise building involves the following steps: For the bottom floors, an axis control network is established on the ground floor as the ground control layer, and a total station is used for vertical transfer using the external control method. For the remaining floors, a reference floor and several floors above it are selected as transition layers for setting up the axis control network. The vertical transfer distance between the transition layers decreases as you go higher. Calculations are performed to ensure that the theoretical projection accuracy of each transition layer is within the allowable range. This ensures that the axis control network is set up in a position that facilitates construction surveying, network transfer, and verification. Then, a laser plumb bob is used to vertically transfer the axis control network upwards segment by segment using the internal control method. After each re-laying of the axis control network at the transition layer, a GNSS measuring instrument is used to check and correct the axis control network, correcting the accumulated error of the previous stage of vertical projection to zero and ensuring that the actual accuracy of the baseline edge and network shape is within the allowable range before upward transfer.

[0006] Furthermore, the method for verifying the theoretical projection accuracy of each transfer layer is as follows: since the cumulative error of the previous stage of vertical projection is corrected to zero, each transfer layer projection stage is considered an independent system. However, each transfer layer projection stage is simultaneously affected by the building's sway, resulting in relative position changes. Therefore, the theoretical projection accuracy m2 of the current transfer layer is:

[0007]

[0008] Among them, s i Considering the unavoidable relative positional change caused by the building's swaying from the next lower transfer floor to the current transfer floor, and assuming that the angle of deviation of the vertical axis from the plumb line at different heights of the building varies proportionally with height, we have:

[0009]

[0010] Where, d i H represents the distance between the i-th layer of projection points; i Let H be the height of the i-th transition layer above the ground, and H be the height of the i-th transition layer above the ground i =d1+d2....+d i H is the total height of the building; α is the maximum angle of deviation of the building's vertical axis from the plumb line, and has A represents the maximum sway of the building, and has The super high-rise building is set to move in the early morning or evening, avoiding adverse external factors such as sunlight, strong winds, and vibrations from large machinery, and only undergoes simple harmonic motion under the influence of wind load. x and y represent the displacement of the building in two directions under the influence of wind load.

[0011] Where m1 is the accuracy of a single point projection, and we have:

[0012]

[0013] Where, m s d represents the point accuracy; m represents the distance between the layers of projection points; d represents the distance between the projection points. y This refers to the relative accuracy of the plumb line.

[0014] Furthermore, the method for verifying the baseline edges of the axis control network on the conversion layer is as follows:

[0015] S1. After the axis control network of the reference layer is laid out, a geodetic quadrilateral is formed by the control points on the ground control layer and the base points on the baseline edge using a GNSS measuring instrument. After static observation and data calculation, the coordinates of the base points on the baseline edge in the GNSS system are obtained, which will serve as the basis for future verification of the axis control network of the high-rise building using GNSS.

[0016] S2. In the conversion layer to be checked, use the method in step S1 to obtain the coordinates of the base point on the baseline edge of the conversion layer to be checked, and compare them with the coordinate data of the reference layer. If the projection error of the corresponding point does not exceed the theoretical projection accuracy of the conversion layer, then the baseline edge does not exceed the allowable error during the transmission process. If the projection error exceeds the tolerance, the cause should be analyzed and readjusted.

[0017] S3. When the structure reaches a certain height during construction, it will vibrate significantly due to wind loads and disturbances from large machinery. Data obtained from static observations cannot be directly used as reference results. Dynamic observation and post-processing methods must be used to improve the accuracy of the results.

[0018] Furthermore, the method for verifying the shape of the axis control network on the conversion layer is as follows: the coordinates of the corner points other than the base point are measured according to the accuracy requirements of the first-order traverse from the set baseline side, the included angle of the corner points is calculated, and compared with the included angle of the corner points of the reference layer. If the error between the two is within the allowable range, the network shape is stable and reliable.

[0019] The beneficial effects of this invention are:

[0020] This method combines internal and external control, significantly reducing measurement time while ensuring accuracy. It considers the verticality of the building's vertical axis and the coaxiality of adjacent floors. A laser plumb line is used to project control points upwards from the lower floors to ensure vertical axis accuracy. Control points on the control network transfer layer closest to the construction floor are used for upward projection. Even in cases of significant curvature and swaying in high-rise buildings, the relative positional change between the construction floor and the control network transfer layer is minimal because they move together with the building. The projection points are controlled within a small, manageable range, thus negligible vertical axis deviation. This ensures the coaxiality of adjacent floors and improves the effectiveness and reliability of vertical measurements in high-rise buildings. Attached Figure Description

[0021] Figure 1 This is a diagram showing the layout of the axis control network for the podium section in an embodiment of the present invention.

[0022] Figure 2 This is a diagram showing the layout of the axis control network for the tower section in an embodiment of the present invention.

[0023] Figure 3 This is a schematic diagram of the vertical transmission of control points in an embodiment of the present invention.

[0024] Figure 4 This is a flowchart of the baseline border inspection process in an embodiment of the present invention. Detailed Implementation

[0025] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0026] A method for measuring the vertical axis of a super high-rise building involves the following steps: For the bottom floors, an axis control network is established on the ground floor as the ground control layer, and a total station is used for vertical transfer using the external control method. For the remaining floors, a reference floor and several floors above it are selected as transition layers for setting up the axis control network. The vertical transfer distance between the transition layers decreases as you go higher. Calculations are performed to ensure that the theoretical projection accuracy of each transition layer is within the allowable range. This ensures that the axis control network is set up in a position that facilitates construction surveying, network transfer, and verification. Then, a laser plumb bob is used to vertically transfer the axis control network upwards segment by segment using the internal control method. After each re-laying of the axis control network at the transition layer, a GNSS measuring instrument is used to check and correct the axis control network, correcting the accumulated error of the previous stage of vertical projection to zero and ensuring that the actual accuracy of the baseline edge and network shape is within the allowable range before upward transfer.

[0027] The following example uses a super high-rise building, Tower C:

[0028] The axis control network is laid out in locations conducive to construction surveying, network transfer, and verification. Tower C has floors 1-9 as a podium and floors 9 to the top as a tower. The axis control network for the podium section is laid out on the first floor slab, using a total station and external control method for vertical transfer. From the 10th floor onwards, the tower section has a new axis control network, using a laser plumb line and internal control method to vertically transfer the axis control network segment by segment upwards. A GNSS measuring instrument is used for vertical transfer via verification and correction at the conversion layer. The network layout for each part is as follows: Figure 1 , Figure 2 As shown.

[0029] Drawing on the displacement data of the Tianjin Chow Tai Fook Financial Center project under two load conditions—considering only wind loads in the x or y directions—as a function of height, the maximum sway A of the supertall building Tower C is determined. Tower C has a total height of 306.9m. To increase data reliability, displacement data at 328.72m from the Tianjin Chow Tai Fook Financial Center project is used as a reference for the maximum sway of Tower C. At this height, the maximum displacements in the x and y directions are x = 136.2mm and y = 144.9mm, respectively. Substituting these values ​​into the formula above, the maximum sway A = 199mm is obtained (the sway A in this model is larger than the actual maximum displacement of the building). Substituting the total height H = 306.9m and the maximum sway A = 199mm into the formula above, the maximum deviation angle α from the vertical axis of the building is determined to be 0.0371603.

[0030] The error of vertical transfer of the upper and lower axis lines of the concrete structure is ≤3mm. The total height of the building is 150<H≤200, and the axis line projection accuracy is ≤30mm. For 200<H, the value is taken as 40% of the construction limit error. According to the floor spacing and construction progress of Tower C, considering that the impact of wind is less when the construction height is low, the vertical transfer distance can be appropriately increased, and the transfer distance is gradually reduced to the upper floor. Combining the requirements of "GB50026-2020 Engineering Surveying Standard", the point projection accuracy analysis formula derived above and the floor height list of the building, the control network conversion layer is set at the four floors of F30, F43, F56 and F66, and F10 is the first internal control point embedding layer.

[0031] Typical point-to-point accuracy (m) s All can be controlled within 2mm, so let's take m here. s The accuracy is 5mm. The commonly used DJZ2 laser plumb bob has an accuracy of m. y The maximum deflection angle α = 0.0371603° and other data are 1 / 45000. Substituting these values ​​into the formula above, the cumulative vertical projection error values ​​at each conversion layer are shown in the table below.

[0032] Table 1. Accuracy Analysis Results of Layered Projection Points

[0033]

[0034] The data in the table above shows that the errors in the vertical projection at each stage are within the allowable range. Each time the axis control network is re-laid at the transition layer, a GNSS measuring instrument is used for verification and correction to zero the accumulated error of the previous stage's vertical projection. After passing the correction, a laser plumb line is used to continue the upward transfer. A schematic diagram of the vertical transfer of control points is shown below. Figure 3 As shown.

[0035] The control network is measured vertically in stages, so the measured axis control network needs to be checked on the floor to be checked. This mainly involves two aspects: baseline edge and network shape.

[0036] After the podium structure is completed, an internal control network is established at the 10th floor of the tower. Because later construction will inevitably damage the control points, the control points within the site are no longer used as reference points for the tower's horizontal control during the vertical construction phase after the 10th floor. To facilitate later verification of the tower's control network, the baseline points N2 and N5 are connected to the primary control points A2 and A3 using GNSS measurements. The coordinates of these two points are then measured and verified using the reference edge coordinates obtained from these two points. The specific operation method is as follows:

[0037] 1) After the 10-layer axis control network is laid out (hereinafter referred to as the 10-layer reference layer), four GNSS measuring instruments are first set up on the primary control points A2 and A3 and the two base points N2 and N5 on the 10-layer baseline to form a geodetic quadrilateral. After static observation and data settlement, the coordinates of the two base points N2 and N5 on the baseline are obtained in the GNSS system. These coordinates will serve as the basis for future GNSS verification of the high-rise axis control network.

[0038] 2) On the floor to be checked, use the same method as in step 1 to obtain the coordinates of the base points N2 and N5 on the baseline edge of the floor to be checked, and compare them with the coordinate data of the reference floor. If the projection error of the corresponding points does not exceed the theoretical design error m2, then the baseline edge has not exceeded the allowable error during the transmission process; if the projection error exceeds the tolerance, the cause should be analyzed and readjusted.

[0039] 3) When the structure reaches a certain height during construction, it will vibrate significantly due to wind loads and disturbances from large machinery. At this time, the data obtained by static observation cannot be directly used as a reference. Therefore, dynamic observation and post-processing methods are used to improve the accuracy of the results.

[0040] Baseline border inspection process as follows Figure 4 As shown.

[0041] The verification of the axis control network shape mainly involves using a total station to measure the coordinates of other internal control points transferred from the original survey, thereby checking whether the transferred network shape has changed. The measurement method involves measuring the coordinates of four corner points (N1, N3, N4, and N6) along the established control network baseline according to the accuracy requirements of a first-order traverse, and calculating the included angles between these four corner points for comparison with the included angles between the four corner points of the reference layer. According to the relevant provisions of the "GB50026-2020 Engineering Surveying Standard," the angular measurement error of the first-order building construction plane control network is... (n is the number of structural spans), with an allowable error of twice the mean square error of the angle measurement. The measured data of the 30th floor of the super high-rise Tower C are compared with the data of the reference floor angle, and the results are shown in Table 3.3-2.

[0042] Table 3.3-2 Mesh Shape Check Measurement Results

[0043]

[0044] The comparison data in the table above shows that the angle values ​​of all four corner points are within the allowable error range, meeting the accuracy requirements, and the mesh type is stable and reliable.

[0045] This method combines internal and external control, significantly reducing measurement time while ensuring accuracy. It considers the verticality of the building's vertical axis and the coaxiality of adjacent floors. A laser plumb line is used to project control points upwards from the lower floors to ensure vertical axis accuracy. Control points on the control network transfer layer closest to the construction floor are used for upward projection. Even in cases of significant curvature and swaying in high-rise buildings, the relative positional change between the construction floor and the control network transfer layer is minimal because they move together with the building. The projection points are controlled within a small, manageable range, thus negligible vertical axis deviation. This ensures the coaxiality of adjacent floors and improves the effectiveness and reliability of vertical measurements in high-rise buildings.

[0046] It should be understood that those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. A method for measuring the vertical axis of an ultra-high building, characterized in that: For the bottom floors, an axis control network is laid out on the first floor as the ground control layer, and a total station is used to transfer the vertical axis control network using the external control method. For the remaining floors, the reference floor and several floors above it are selected as the transition layers for laying out the axis control network. The vertical transfer distance between the transition layers decreases as you go up. Calculations are performed to ensure that the theoretical projection accuracy of each transition layer is within the allowable range. The axis control network is laid out in a position that is conducive to construction surveying, network transfer, and verification. Then, a laser plumb bob is used to transfer the axis control network vertically upwards segment by segment using the internal control method. After the axis control network is re-buried in the transition layer each time, a GNSS measuring instrument is used to check and correct the axis control network, correct the cumulative error of the previous stage of vertical projection to zero, and ensure that the actual accuracy of the baseline edge and network shape is within the allowable range before it can be transferred upwards. The method for verifying the theoretical projection accuracy of each transfer layer is as follows: since the cumulative error of the previous stage of vertical projection is corrected to zero, each transfer layer projection stage is considered an independent system. However, each transfer layer projection stage is simultaneously affected by the building's sway, resulting in relative positional changes. Therefore, the theoretical projection accuracy of the current transfer layer... for: in, Considering the unavoidable relative positional change caused by the building's swaying from the next lower transfer level to the current transfer level, and assuming that the angle of deviation of the vertical axis from the plumb line at different heights of the building varies proportionally with height, we have: in, The distance of the i-th layer projection point; Let be the height of the i-th transition layer above the ground, and have H is the total height of the building; α is the maximum angle of deviation of the building's vertical axis from the plumb line, and has A represents the maximum sway of the building, and has The super high-rise building is set to move in the early morning or evening, avoiding adverse external factors such as sunlight, strong winds, and vibrations from large machinery, and only undergoes simple harmonic motion under the influence of wind load. x and y represent the displacement of the building in two directions under the influence of wind load. in, For the accuracy of a single point projection, and given: in, d represents the point accuracy; d represents the distance between the layers of projection points. This refers to the relative accuracy of the plumb line.

2. The method for measuring the vertical axis of a super high-rise building as described in claim 1, characterized in that: The method for checking the baseline edges of the axis control network on the conversion layer is as follows: S1. After the axis control network of the reference layer is laid out, a geodetic quadrilateral is formed by the control points on the ground control layer and the base points on the baseline edge using a GNSS measuring instrument. After static observation and data calculation, the coordinates of the base points on the baseline edge in the GNSS system are obtained, which will serve as the basis for future verification of the axis control network of the high-rise building using GNSS. S2. In the conversion layer to be checked, use the method in step S1 to obtain the coordinates of the base point on the baseline edge of the conversion layer to be checked, and compare them with the coordinate data of the reference layer. If the projection error of the corresponding point does not exceed the theoretical projection accuracy of the conversion layer, then the baseline edge does not exceed the allowable error during the transmission process. If the projection error exceeds the tolerance, the cause should be analyzed and readjusted. S3. When the structure reaches a certain height during construction, it will vibrate significantly due to wind loads and disturbances from large machinery. Data obtained from static observations cannot be directly used as reference results. Dynamic observation and post-processing methods must be used to improve the accuracy of the results.

3. The method for measuring the vertical axis of a super high-rise building as described in claim 1, characterized in that: The method for verifying the shape of the axis control network on the conversion layer is as follows: the coordinates of the corner points other than the base point are measured according to the accuracy requirements of the first-order traverse from the set baseline side, the included angle of the corner points is calculated, and the included angle of the corner points is compared with that of the corner points of the reference layer. If the error between the two is within the allowable range, the network shape is stable and reliable.

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